Cutting panels, especially panels having a decorative coating layer on one side, such as wall paneling, by means of a circular handsaw, involves the problem that the cut edge can look frayed on the "good" side of the panel. Thus, cutting may have to be done on the backside of the panel, which is inconvenient because the lines to be cut must be drawn on the back of the panel as a "negative" so that the correct cut appears on the front or "good" side of the panel. This problem is especially pronounced where the surface coating is hard and brittle.
To avoid the above problem, German Patent Publication (DE-OS) 3,800,935 describes a method of cutting panel work pieces made of wood or the like, such as plywood or chip-board panels having a cover layer or coating of plastic or hard paper, by means of a handheld circular saw which has, in addition to the normal saw blade, a special prescoring saw blade for first scoring or cutting only the cover layer in a saw moving direction which is "synchronous", so to speak, with the rotation direction of the saw blade. Then, the regular cutting saw blade is used to completely cut through the work piece in a direction opposite to that of the saw blade rotation. In this manner it is prevented that the brittle cover layer is torn or splintered by the main cutting saw blade during its cutting operation in a counter-running direction. As mentioned, the known saw needs a scoring blade in addition to the normal cutting blade, whereby the structural supporting and drive for the separate scoring blade makes the handheld circular saw more troublesome, heavier, and more expensive.
In order to achieve satisfactory straight saw cuts in a simple manner it is generally known in the art to set the handheld circular saw onto a guide edge which has been positioned on the work piece, whereby a groove in the base plate of the circular saw cooperates with or slidingly engages a rib of the guide edge.